Yet another name for it (but in ceramics) could be "Fat Lava". I'm sure it must be a silimar sort of enamel. It looks as if they've used the general Harris design, but managed to incorporate this sort of finish.

It is. I think the word "gros", meaning large, got mistranslated into "fat". However, this looks like "thin" lava, if you like - I was referring to the actual surface texture of the enamel, not its thickness.